The Rec Comtal canal is a thousand years old (two thousand if we add its previous use as a Roman aqueduct) and it has always been under the pavement. It starts in Montcada i Reixac and then zigzags across nine of Barcelona's eleven. Roadworks sometimes make this imposing hydraulic structure emerge and cease to be invisible. It has happened this week in the Meridiana, where a section three meters deep has surfaced between Trinxant and Nació. The abutments of a bridge of the Northern Railway and an irrigation ditch have also been found.